4-tert-butylcyclohexanol

Biodegradation in water and sediment: simulation tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: sediment simulation testing

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Justification for type of information:

Data is from computational model developed by USEPA

Qualifier:

according to guideline

Guideline:

other: Modeling database

Principles of method if other than guideline:

Fugacity Model by EPI Suite estimation database

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of test material (IUPAC name): 4-tert-butylcyclohexanol
- Molecular formula : C10H20O
- Molecular weight : 156.267 g/mol
- Smiles notation : C(C1CCC(O)CC1)(C)(C)C
- InChl : 1S/C10H20O/c1-10(2,3)8-4-6-9(11)7-5-8/h8-9,11H,4-7H2,1-3H3
- Substance type: Organic
- Physical state: Solid

Radiolabelling:

not specified

Oxygen conditions:

other: estimation

Inoculum or test system:

not specified

Parameter followed for biodegradation estimation:

test mat. analysis

Details on study design:

Level III Fugacity model
EPI Suite contains a Level III fugacity model. In general, fugacity models predict the partitioning of an organic compound in an evaluative environment. A Level III model assumes steady-state but not equilibrium conditions. The Level III model in EPI Suite predicts partitioning between air, soil, sediment and water using a combination of default parameters and various input parameters that may be user defined or estimated by other programs within EPI Suite.

The model environment consists of 4 main compartments: air, water sediment and soil. There are also sub-compartments such as an aerosol phase, suspended solids, and biota phase, within specific main compartments. A fixed temperature of 25ᵒC is assumed. Mass transport between the compartments via volatilization, diffusion, deposition and runoff are modeled. level III models is a steady state, non-equilibrium model. Steady state conditions mean that the change in concentration of a chemical in each compartment (i) with respect to time eventually approaches zero. The model does not assume that a common equilibrium (fugacity) exists between the phases, so if a chemical is emitted into one compartment it can partition to the other compartments. Loss of chemical occurs through two processes: reaction and advection. Reaction is the biotic or abiotic degradation of the chemical that is calculated using the user specified or model calculated half-lives of the chemical in each of the 4 main compartments. Advection processes are considered for the air, water and sediment compartments. Advection is the removal of chemical from a compartment through losses other than degradation (reaction). The rate of advection in a given compartment is determined by a flow rate (m3/hour), calculated by dividing the volume of the compartment by an advection time.

Compartment:

water

% Recovery:

28.4

Remarks on result:

other: Other details not known

Compartment:

sediment

% Recovery:

0.141

Remarks on result:

other: Other details not known

Key result

% Degr.:

50

Parameter:

other: Half-life in water

Sampling time:

15 d

Remarks on result:

other: Other details not known

Key result

% Degr.:

50

Parameter:

other: Half-life in sediment

Sampling time:

135 d

Remarks on result:

other: Other details not known

Key result

Compartment:

water

DT50:

15 d

Type:

other: estimated data

Temp.:

25 °C

Remarks on result:

other: Other details not known

Key result

Compartment:

sediment

DT50:

135 d

Type:

other: estimated data

Temp.:

25 °C

Remarks on result:

other: Other details not known

Transformation products:

not specified

Evaporation of parent compound:

not specified

Volatile metabolites:

not specified

Residues:

not specified

	Mass Amount (percent)	Half-Life (hr)	Emissions (kg/hr)
Water	28.4	360	1000
Sediment	0.141	3.24e+003	0

 

	Fugacity (atm)	Reaction (kg/hr)	Advection (kg/hr)	Reaction (percent)	Advection (percent)
Water	2.42e-010	683	355	22.8	11.8
Sediment	2.11e-010	0.377	0.0353	0.0126	0.00118

Validity criteria fulfilled:

not specified

Conclusions:

Estimated half life of test chemical 4-tert-butylcyclohexanol in water was 15 days (360 h) and in sediment estimated to be135 days (3240 h).

Executive summary:

Estimation Programs Interface (EPI Suite, 2018) prediction model was run to predict the half-life in water and sediment for the test compound 4-tert-butylcyclohexanol (CAS No. 98 -52 -2). If released in to the environment, 28.4% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 4-tert-butylcyclohexanol in water is estimated to be 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of 4-tert-butylcyclohexanol in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.141%), indicates that 4-tert-butylcyclohexanol is not persistent in sediment.

 

Description of key information

Estimation Programs Interface (EPI Suite, 2018) prediction model was run to predict the half-life in water and sediment for the test compound 4-tert-butylcyclohexanol (CAS No. 98 -52 -2). If released in to the environment, 28.4% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 4-tert-butylcyclohexanol in water is estimated to be 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of 4-tert-butylcyclohexanol in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.141%), indicates that 4-tert-butylcyclohexanol is not persistent in sediment.

 

Key value for chemical safety assessment

Half-life in freshwater:

15 d

at the temperature of:

25 °C

Half-life in freshwater sediment:

135 d

at the temperature of:

25 °C

Additional information

Various predicted data for the target compound 4-tert-Butylcyclohexanol (CAS No. 98-52-2) were reviewed for the biodegradation in water and sediment end point which are summarized as below:

 

In aprediction done using the Mackay fugacity model level III of Estimation Programs Interface (EPI Suite, 2018) was run to predict the half-life in water and sediment for the test compound 4-tert-Butylcyclohexanol (CAS No. 98-52-2).If released in to the environment, 28.4% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 4-tert-butylcyclohexanol in water is estimated to be 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of 4-tert-butylcyclohexanol in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.141%), indicates that 4-tert-butylcyclohexanol is not persistent in sediment.

 

In a supporting study from secondary source (Robust Summaries & Test Plans: Cyclohexy Derivatives Category: Revised Summaries, 2006) and HPVIS, 2017, half-life of the chemical 4 -tert-Butylcyclohexanol (CAS No: 98-52-2) in water and sediment by using Mackay EQC Fugacity Level III. The following values has been used in the Mackay EQC Fugacity Level III for the estimating the half-life value. They are water solubility: 100 mg/l, vapour pressure: 0.0075 mm Hg, log Kow: 3.23 and melting point: 55-70°C, respectively. If released into the environment, 38.1% of the chemical will partition into water according to the Mackay EQC Fugacity Level III and the half-life period of 4 -tert-Butylcyclohexanol in water is estimated to be 15 days (360 hrs). The half-life (15 days estimated by Mackay EQC Fugacity Level III) indicates that the chemical 4-tert-Butylcyclohexanol is not persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of 4-tert-Butylcyclohexanol in sediment is estimated to be 60 days (1440 hrs). Based on this half-life value of test chemical 4-tert-Butylcyclohexanol, it is concluded that the chemical 4-tert-Butylcyclohexanol is not persistent in the sediment environment and the exposure risk to soil dwelling animals is moderate to low.

 

On the basis of above results for target chemical 4-tert-Butylcyclohexanol (from EPI suite, 2018 and secondary source), it can be concluded that the test substance 4-tert-Butylcyclohexanol is not persistent in the water and sediment environment and therefore the exposure risk to aquatic and soil dwelling animals is moderate to low.